It is desirable to permit pets regular access to outside, such as for example, to a fenced in yard for various reasons. There exists pet doors that are permanently installed on exterior doors that operate to permit a pet to have access to the outside. However, these existing pet doors require modification of the door to which they are installed, including cutting an opening through the door. There are circumstances where cutting an opening through the door is not desired or is not possible due to the type of door, for example french doors. Accordingly, there is a need for a new device that can be temporarily installed in a doorway and which permits passage of a pet.